NPR producer Sam Sanders headed to Beverly Hills, Calif., recently to see longtime fitness guru Richard Simmons in action and find out how he has been at it so long. He sent this reporter's notebook of his encounter with the man who's been helping people lose weight for nearly 40 years.

While working as a waiter, Richard Simmons saved up a year-and-a-half worth of tips to open his first aerobics studio in Beverly Hills in 1974. Ever since then, he has been planting himself in America's pop-culture psyche with dozens of infomercials and best-selling books, myriad parodies of his over-the-top persona, and seemingly endless TV and film appearances.

Imagine my excitement at a dinner party last spring, when a friend of a friend told me about Simmons' Beverly Hills aerobics classes. Turns out, whenever Simmons is in town, he leads the courses himself, in that same studio he moved into nearly four decades ago. The classes are open to the public, cost only $12, and they have a cult following in Los Angeles. I knew I had to go, and record it.

So, I convinced Simmons' team to let me shadow him one Saturday afternoon in May, traipsing behind the dynamo — with a big fuzzy shotgun mic in hand.

When I walked into the studio, Simmons was in the middle of one of his iconic pep talks — part AA meeting, part church testimony service. He had on a handmade glittery shirt and tank-top ensemble (with two-toned tights, of course), and was circled up on the floor with a lot of people who really wanted to lose weight. As a larger, middle-aged woman started crying while telling Simmons about her weight-loss goals, Simmons broke up the tension in that earnestly wacky way only he can.

He talked about his underwear.

"When you lost the weight, did you buy new underwear? Doesn't it feel good to buy new underwear?" Simmons said, drawing awkward laughter. "When I lost my weight, I went and bought about 15 different types of underwear to see what would look good on my new body. It's exciting!"

The next hour became a full-on dance riot. Simmons' "Sweatin' to the Oldies" soundtrack had been replaced by an incredibly modern playlist — Pitbull meets Ibiza meets Katy Perry. The crowd was mixed, men and women, straight and gay, fat and skinny.

Simmons was a whirling dynamo of energy — a spastic, sweaty Svengali. He'd reach to turn down the music in the middle of a song, just to yell out affirmations: "I love you all!" or "I just wanna lick your neck!" He'd tell the sweating bodies gathered around him how dancing is just like making love.

When he stopped the music for some weight lifting, he'd spontaneously burst out singing. An eight-beat countdown would be interrupted by a screeching rendition of "The Birds and the Bees." When he was really feeling the spirit, he'd craft an original, like "Go Away Chubby Thighs," which he began belting about 45 minutes in.

Simmons led a dance circle in the middle of the mirrored studio, bringing writhing, shirtless and exposed bodies into the center to shake. He told one woman she was cute "like a dessert," and one unassuming man even received an offer from Simmons to wax his legs, because he was just too hairy.

As Simmons told me in an interview after the class, "it's a Broadway show."

"The more I bark at them and become different characters and drive them crazy, the harder they work," he said, adding that he likes the tension. "I get a little thrill out of driving them crazy, just a little."

But all of it — the sweat, the innuendo, the unabashed libido — it serves a higher purpose for Simmons. As we talked in the empty studio, after he had taken photographs and signed shirts and body parts, he softly wept as he told me about the seriousness of what he does.

"Even though my work is whimsical," Simmons says, "I have a very serious job. I cry more than I laugh."

Contrary to popular belief, Simmons is not a jester. He is a minister.

"When I go to bed at night, I ask God to give me another day," he says. "I ask him to keep me strong and make me a good teacher, and to keep spreading this right word."

That "right word" — his life's work — is almost holy in its simplicity. For his entire professional life, his message has been: "Work hard, take care of yourself, and you'll be just fine."

And the messenger says he's not stopping anytime soon.

"I have to do it till the day I die," he says. "If I don't move, I'm not happy."

By that measure, Simmons will be happy long into the foreseeable future.

Copyright 2012 National Public Radio. To see more, visit http://www.npr.org/.

Transcript

DAVID GREENE, HOST:

Remember this guy?

RICHARD SIMMONS: This is my brand-new aerobic workout tape, "Sweating to the Oldies," and if you don't like having fun...

(LAUGHTER)

SIMMONS: ...well, you best not come in here. Whew!

GREENE: Fun. Yes, that's Richard Simmons. And here's your interesting fact for the morning. Before he became a fitness icon, Simmons was a struggling waiter. He saved up a year and a half of tips to open an aerobics studios in Beverly Hills. Thirty-nine years later, after selling millions of fitness books and videos, he is still in that same studio, still teaching, still sweating to the oldies with anyone who will show up for his $12 sessions.

Well, NPR News producer Sam Sanders showed up for a workout and saved up just enough energy to send us this postcard.

SIMMONS: Stomach in, four and five, push it back, six and seven and eight. Say yeah.

UNIDENTIFIED GROUP: Yeah.

SIMMONS: (Singing) Let me tell you about the birds and the bees and the flowers and the trees and the moon up above. One. And a thing called love.

THE BUGGLES: (Singing) Video killed the radio star, video killed the radio star.

SIMMONS: I love you all.

(SOUNDBITE OF CHEERING)

SIMMONS: My friend, Gerry, who's been coming here for many years, and she's just celebrated her 90th birthday.

(APPLAUSE)

GERRY SINCLAIR: My name is Gerry Sinclair. I'm 90, and I celebrated right here at Richard Simmons, didn't I?

UNIDENTIFIED WOMAN #1: Yes, you did.

SINCLAIR: It was such fun.

JOHN RANDALLS: My name's John, John Randalls, first time.

SAM SANDERS, BYLINE: Why'd you come?

RANDALLS: 'Cause Richard Simmons is a living legend.

UNIDENTIFIED WOMAN #2: Because it's here.

RANDALLS: And because it's here. Yeah. And if I had an opportunity to spend $12 and spend my morning with Richard Simmons, I was going to do it.

SIMMONS: You know, it's a Broadway show. It is not an easy workout. You know, these people did close to most probably five or six hundred leg lifts today. But most of all, it did something for their self-esteem. And the more I bark at them and become different characters and drive them crazy, the harder they work.

UNIDENTIFIED MAN: He said I was a hairy, hairy man, and he offered to wax my legs for me. So that was quite an experience.

NATALIE: He said I was cute, like a dessert, and it was amazing. He thought I was 16. He thought I looked too young to be in a class like this, I guess. I don't know.

SANDERS: How old are you, Natalie?

NATALIE: I'm 31.

(LAUGHTER)

SIMMONS: I get a little thrill out of driving them crazy. Just a little bit, and then they'll go home and go, Do you know what he said to me?

UNIDENTIFIED MAN #2: Well, he made eye contact with me, because I knew he was about to like take me into that dance circle. And then he like whispered in ear to take my (bleep) shirt off. And I looked at him, a little confused. And then he looked at me again with kind of a sinister kind of like grin and he said, take your (bleep) shirt off. So I took my (bleep) shirt off and I started dancing with Richard Simmons.

(SOUNDBITE OF MUSIC)

SIMMONS: Even though my work is whimsical, I have a very serious job. I cry more than I laugh. When I go to bed at night, I ask God to give me another day. Every night that I go to bed. I ask him to keep me strong and make me a good teacher and to keep spreading this right word. And, you know, I have to do it till the day I die.

GREENE: That is Richard Simmons. NPR's Sam Sanders spent a day with him at his aerobics studio in Beverly Hills. Transcript provided by NPR, Copyright National Public Radio.